Where in Florida are you moving to? I'm just outside of Orlando.
I have been using my garage as a workshop since we moved into this house in the late 80s. Our garage is connected directly to teh rest of the house, all yo have to do is open a door at the end of a short hall and it's there. I keep my ecals in teh house in plastic boxes from, work that held packs of labels and they are in a drawer in a spare room that serves as a office.
The models are kept in the garage, mostly on top of shelves that go almost to the ceiling. Some are kept in plastic closets that line th wall.
Not long after we moved in I put rolls of insulation in the space between teh roof and the cieling of the garage. I picked a type that came sealed so I didn't have to put up with loose material getting all over me. I also got hold of sheets of a foam insulation and put sheets of it along the outer wall that faced the sun and panels into the sections of the garage door that faces the east and takes the full impact of the morning sun until about 11:00 or so. I can get away with a window fan that has adjustable blades so I canhaveone working to suck out the hot air and the other to blow right into the area that I work on. Now sometimes I use one of those compact square personal A/C units that they advertise of T.V. If I'm working at night or sometimes during the day it takes the edgeoff the heat. Just keep it filled with water.